A. Field of the Invention
This invention relates to cylinder head assemblies for internal combustion engines which have intake and exhaust valves. More particularly, the invention relates to an improved rocker arm for operating the valves.
B. Description of the Art
Many engines have the cam shafts and rocker arms placed in elevated positions above the valve member. This design is not compact and requires extra linkages.
Others employ push rods to activate rocker arms with the push rods positioned at the side of the cylinders. This interferes with cooling, and also takes up some space that could be otherwise used for other engine components.
In the instance where the rocker arm has been positioned lower in the engine head (e.g. U.S. Pat. No. 3,563,214) and without the use of rocker push rods, there is a problem with the rocker arm having the strength to withstand contact forces by the camming surface as the cam shaft engages the rocker arm in a lateral manner. Also, the forces the rocker arm exerts on the valve stem act around a fulcrum and thus have a substantial undesired lateral vector component.
An improved rocker arm is therefore desired.